For now I'd play as a free agent, mostly because I see things getting messy- Most factions want land in one form or another, although I imagine that Chaladon will be quite isolationist, or will try to expand to the south. There's economic tension between the Guild and Empire, who run competing trade routes. Arashi will feed off them as they fly through their lands, being raided left right and center. I think the Baronies and the Angleans wlll duke it out for Anvala, but as the Yeshans cross the wastes they'll be forced to face them together or be wiped out. In a lore perspective, I imagine that's the relationship between the factions.
Currently, I'll go Baronies, as they're gonna see a lot of action.